Automatic test equipment for the testing and measurement of electronic signals and waveforms is known. Frequently, existing test instrumentation utilizes hardware components that have become obsolete and unmaintainable. The cost to replace the entire test instrument is typically very high due to its impact on test and software applications. Additionally, maintenance of the test instrument's original designed components to extend service life is limited due to obsolescence and reliability issues experienced with older technology. All these issues prohibit utilization for limited budgeted systems.
In some test instrumentation, Electron Bombarded Semiconductor (EBS) tubes are used for analog-digital conversion. As with other test instrument components, these EBS tubes are also subject to obsolescence.
One methodology used to extend service life and mitigate the issues of obsolescence and reliability is to replace the special Electron Bombarded Semiconductor (EBS) Tubes with current technology that is functionally the same yet reliably superior. By utilizing new technology, the overall cost of maintaining the test instrument is reduced while utilization is enhanced. Applied to multiple systems where the instrument is used, the benefits are profound.
To provide an understanding of the application of the invention, FIG. 1 shows major subsystems of a prior art automatic test equipment capable of measuring waveforms via programmable by digitization. Specifically, FIG. 1 shows a block diagram of an IATS Programmable Waveform Digitizer 100 in which the major functional subsystems, aside from an analog-to-digital conversion subsystem, are shown. One skilled in the art would be readily able to ascertain the manner in which the waveform digitizer 100 operates and the function of each subsystem.
As the invention relates in particular to an analog-to-digital conversion block for such a programmable waveform digitizer 100, the prior art analog-to-digital conversion (ADC) block is shown in FIG. 2 and designated generally as 102. ADC block 102 includes, for each of Channel A Input and Channel B input thereto, an EBS tube 104.
In a manner known to those skilled in the art, the EBS tubes 104 are used to perform analog-to-digital conversion. One special EBS tube for this purpose is an electron tube with a silicon target, an electron gun, focus lenses and alignment plates using a 10-kilovolt beam to convert an input analog signal to a digital format. The tube requires a high voltage supply to develop the 10-kilovolt beam and precise alignment in order to accurately perform the analog-to-digital conversion. Additionally, skilled technical personal are required to periodically perform a detailed calibration procedure.
Each EBS tube 104 interfaces with a deflection amplifier 106 and a clock buffer 108 which provides a strobe for sampling, for example, at five nanosecond intervals (200 Mps) (see FIG. 1). The deflection amplifiers 106 provide analog input for sampling by the EBS tubes 104. A high voltage supply 110 is also provided as either part of the ADC block 102 or one of the subsystems in the programmable waveform digitizer 100. The high voltage power supply 110 provides the voltage required to develop a 10-kilovolt beam to convert an input analog signal into digital form. The programmable waveform digitizer 100 also includes a data memory interface component 112 which receives the Channel A and B data from the ADC block 102. Data memory interface component 112 is typically constructed to be capable of storing 8 bit gray coded outputs.
As discussed above, since the EBS tubes 104 are therefore obsolete, it would be desirable to replace them, and ideally the entire ADC block 102 containing them.